Currently available radiologic imaging techniques makes it possible to display a localized focus of disease deep within specific organs or tissues of the body. A typical example is the visualization of a small cancerous mass in the breast of a woman. In order to accurately diagnose and effectively treat the disease, the mass in the breast, it may be necessary for a surgeon to excise a portion of the diseased tissue for microscopic examination and analysis. A recurrent problem for the physician and surgeon is that even with the help of X-ray films, the surgical search for a small lesion or mass often proves extremely difficult; can cause considerable damage to the normal tissues surrounding the lesion; and often fails in the attempt.
In recent years the surgery, commonly termed a biopsy procedure, has been greatly simplified by the radiologist placing a long, wire marker having a small hook or spur at one end into the tissue, under radiological control. Once the wire hook has been inserted at the chosen site, films are taken to document the exact relationship of the wire to the target lesion. The wire length serves as a marker and guides the surgeon to the suspected lesion or mass. Presuming that the wire guide has been accurately positioned, the biopsy can be performed rapidly and accurately. Unfortunately, if the wire guide is shown by radiological examination, to be improperly situated, one or more additional hooked wires must be inserted into the tissue and subsequently verified radiologically as being in the proper localized site. Once inserted, accurately or inaccurately, it is usually the surgeon who will remove the wire markers at the time of biopsy because the hooked end of the wire is embedded in the tissues and cannot be easily withdrawn without tearing the surrounding tissues.
A variety of different wire guides and needle devices have been developed to aid the surgeon in the biopsy procedure and are in routine use today. These conventionally available wire guide devices are of four general types: the Frank localizer; the Kopans locater; the Homer needle/wire localizer; and the Sadowsky needle marking system. Each of these will be described individually in detail.
The Frank localizer is illustrated in cross-sectional view by prior art FIG. 11A and typically consists of a 12 centimeter (hereinafter "cm") wire with a 5 millimeter (hereinafter "mm") hook or spur at the tissue insertion end. The hooked wire is typically carried by a 20 gauge syringe needle having about a 9 cm length. While the length of the wire is inserted into the bore of the syringe needle, the hook remains outside the needle tip during its introduction into the body tissue at the preselected site of insertion. Unfortunately, once the wire and needle has been inserted at the chosen site, the needle can only be advanced deeper into the tissue; it cannot be withdrawn even slightly without releasing the wire into the tissues. The wire itself cannot be repositioned at any time, even if it is not situated close enough to the target lesion. Furthermore, the wire is extremely thin, difficult to palpate, and may be accidentally cut during the surgery.
The Kopans locater is illustrated in cross-sectional view by prior art FIG. 11B. As designed, the wire length and hooked end are intended to remain within the bore of the needle during insertion into the tissues. Once positioned, the beveled needle tip is checked radiologically for proximity to the target area; if incorrectly situated, the needle can be adjusted if necessary. Once believed to be in the correct target area, the wire hook within the bore of the needle is extended and thereby released into the surrounding tissue. The hollow needle is then typically removed leaving the hooked wire in the extended position within the tissue. There are, however, some flaws in the Kopans system. The tip of the needle is not completely secure in the tissue after insertion and prior to release of the wire hook; it may become displaced by involuntary movement of the subject between the time the needle position is radiologically checked and the wire hook is finally extended. Also, the entire wire length may be drawn into the tissues during the position verification procedure; accordingly either the tissue, such as a breast, must be kept in constant compression or an external screw-clamp must be utilized to prevent the length of the wire from being drawn into the tissues and lost. The wire within the needle bore typically has a thickened segment along its length to assist surgical palpatation, but may become broken or accidentally cut above or below this. Since the needle lumen must accommodate both the hook and the shaft of the wire, the wire diameter can be no more than half the diameter of the lumen, or one quarter of its cross-sectional area. This necessitates a larger bore needle for any required wire thickness.
The Homer needle/wire localizer is illustrated in cross-sectional view by prior art FIG. 11C. Typically, the device comes in either long or short length formats. A beveled syringe needle is utilized into which is inserted a J-shaped wire formed from a metal with strong spring recovery which can be temporarily straightened as it is drawn into the bore of the needle. Typically, a wire screw-clamp is attached to the wire at its proximal end to indicate the orientation of the J-shaped hook and to provide some indication of the depth of wire in the needle and tissues. During insertion of the needle into the tissues, the J-shaped hook remains within the bore of the needle. Once the tip of the needle is found to be in the desired area of the target lesion, the wire is extended through the needle bore and the J-shaped hook pushes out into the surrounding tissue in a sweeping curve. The needle is optionally left in place within the tissue along with the wire during the biopsy. The needle, however, is difficult to control during insertion such that the J-shaped hook may be delivered at an unintended location. It is very easy to overextend past the target area and equally common to extend at an inappropriate angle because of the J-shaped hook configuration. Furthermore, withdrawing the needle can result in a cutting sweep of tissue by the J-shaped hook as it is retracted into the bore of the needle. Finally, while the clamp at the proximal end of the wire is meant to indicate the orientation of the J-shaped hook, it is common for the wire to become twisted or disoriented with relation to the screw-clamp.
The Sadowsky marking system is illustrated in cross-sectional view by prior art FIG. 11D. The Sadowsky needle and wire guide is similar to the Kopans device previously described herein. A hooked wire is intended to remain within the bore of the beveled edge needle during insertion of the device into the tissue. A screw clamp is typically mounted on the outside of the needle to a preset needle depth believed to be appropriate for the target lesion. The wire also usually has individual markings along its length to identify its depth as well. Once the needle has been inserted into the tissue and been verified as to correct positioning, the hooked wire is advanced out of the needle bore into the tissue substantially as shown. Once advanced into the tissue, the hooked wire cannot be withdrawn or repositioned. The other deficiencies of the Sadowsky system are similar to those enumerated for the Kopans system previously.
Clearly, there is a recognized and continuing need for a biopsy guide device which is adjustable, removable without destruction of localized tissue, and can be repositioned if necessary without need for either additional guide devices or further damage to the patient. The availability of such an adjustable biopsy guide would be recognized and acknowledged by physicians and surgeons alike as being a valuable advance in this art.